The Web has become a ubiquitous environment for application delivery. The originally intended idea, as a distributed system for knowledgeinterchange, has given way to organizations offering their products and services using the Web as a global point of sale. The centralized delivery-mechanism enables the construction of E-Commerce applications personalized for each user by using behavior analysis. Current technologies suffer from the Web's legacy and use Log file-analysis or collaborative filtering only to adapt the content to users' needs. Motivated by the results of collaborative filtering ms, we describe a construction approach based on the abstract concept of services. To support the fine-grained concept we use the component-based WebComposition Markup Language to support reuse and seamless evolution of E-Commerce applications.